A few years ago I discovered the beauty of shell illustrations through the works of George Sowerby. Here are a few that I've found particularly enjoyable to look at from him and others.
Species conchyliorum by Sowerby -highlight and other images -original book context
Japanische Meeres-Conchylien by Lischke —highlight and other images -original book context
Thesaurus conchyliorum by Sowerby -highlight and other images -original book context
Nicolaus Georg Gevens Conchylien by Bachmann, Friedrich and Geve, Nicolaus Georg -highlight and other images -original book context
Neues systematisches Conchylien by Martini, Friedrich and Heinrich Wilhelm -highlight and other images -original book context
I do like shells! Similarly, you may be interested in ammonite illustrations. They're quite beautiful. For me, I find bubble and cloud chamber images particularly lovely. They're so gorgeous and chaotic, and a little surreal! 